diff --git a/Lib/inspect.py b/Lib/inspect.py index a65aafdb1b8..4e33a22e310 100644 --- a/Lib/inspect.py +++ b/Lib/inspect.py @@ -1594,8 +1594,9 @@ def _signature_bound_method(sig): def _signature_is_builtin(obj): # Internal helper to test if `obj` is a callable that might # support Argument Clinic's __text_signature__ protocol. - return (isinstance(obj, _NonUserDefinedCallables) or + return (isbuiltin(obj) or ismethoddescriptor(obj) or + isinstance(obj, _NonUserDefinedCallables) or # Can't test 'isinstance(type)' here, as it would # also be True for regular python classes obj in (type, object))